Observations sur les microfaciès des roches sédimentaires prélevées sur la marge armoricaine

L'étude des dragages de roches et de sédiments effectués sur la marge armoricaine entre 47 et 48, de latitude Nord permet d'en préciser l'évolution paléogéographique et tectonique et de l'intégrer à celle du golfe de Gascogne. L'analyse de mi crofaciès des échantillons rocheux dont l'âge varie du Jurassique supérieur au Néogène met en évidence - d'une part, l'appartenance de la bordure nord de la marge armoricaine au domaine mésogéen au moins jusqu'au Crétacé moyen; - d'autre part, la permanence d'un régime de plate-forme carbonatée qui paraît fonctionner du Tithonique au Tertiaire inférieur, sur laquelle ont pu s'installer des édifices récifaux notamment au Crétacé moyen. Pendant toute cette période la sédimentation a compensé la subsidence; - enfin, l'accentuation de la subsidence à partir de l'Éocène (accompagnée d'une diminution de la production de calcium $) qui est vraisemblablement en relation avec les phénomènes tectoniques majeurs qui ont affecté à ce moment la bordure sud de la plaque européenne

GFOC Project results: High Temperature / High Pressure, Hydrogen Tolerant Optical Fiber

Tests results are given for exposure of multimode optical fiber to high temperatures (300 deg. C) and high partial pressure (15 bar) hydrogen. These results demonstrate that fluorine down doped optical fibers are much more hydrogen tolerant than traditional germanium doped multimode optical fibers. Also demonstrated is the similar hydrogen tolerance of carbon coated and non-carbon coated fibers. Model for reversible H2 impact in fiber versus T{sup o}C and H2 pressure is given. These results have significant impact for the longevity of use for distributed temperature sensing applications in harsh environments such as geothermal wells

Annotated record of the detailed examination of Mn deposits from R/V "Le Suroit" GEOMANCHE75/1 stations

We report here preliminary results from the detailed sampling of granitic basement at a depth of 4.000 m at the lower edge of the Armorican continental margin near 48°N and 12°W. We consider that we have sampled here the extreme lateral limit of the continental crust where local exposures emerge from under a cover of Cainozoic,Mesozoic and probable Palaeozoic sediments

Efficient photo-thermal activation of gold nanoparticle-doped polymer plasmonic switches

International audienceWe report on the photo-thermal activation of dielectric loaded plasmonic switches comprised of gold nanoparticle-doped polymer deposited onto a gold film. The plasmonic switches rely on a multi-mode interferometer design and are fabricated by electron beam lithography applied to a positive resin doped with gold nanoparticles at a volume ratio of 0.52%. A cross-bar switching is obtained at telecom wavelengths by pumping the devices with a visible beam having a frequency within the localized surface plasmon resonance band of the embedded nanoparticles. By comparing the switching performances of doped and undoped devices, we show that for the modest doping level we consider, the power needed to activate the doped switches is reduced by a factor 2.5 compared to undoped devices. The minimization of activation power is attributed to enhanced light-heat conversion and optimized spatial heat generation for doped devices and not to a change of the thermo-optic coefficient of the doped polymer

Annotated record of the detailed examination of Mn deposits from R/V "Jean Charcot" GEOMANCHE 76/2 stations

This report presents the preliminary results of the study of rocks and sediments obtained by dredging during four cruises of the R/V Jean Charcot and R/V Le Suroit during a cooperative program between CNEXO and CEPM (CH 58: April 1975; SU 01: December 1975; CH 66: February 1976; and CH 67: March 1976). Several dredges on the continental slope of the Goban Spur recovered "granitic" rocks on two morphological structures, Granite Cliff and "Menez Bihan" (Pautot et al., 1976), in water depths ranging from 3200 to 4200 meters. According to the radiometric age and petrology, the granodiorite appears to have a close affinity with similar igneous facies which have been described in Iberia (Capdevilla et al., 1973) and attributed to the Variscan intrusive episode which is also found in the nearby continental area (southwest Great Britain and Brittany, France). They often are coated by a centimeter-thick layer of ferromanganiferous deposits (Shaaf et al., 1977)

Impact of manual lymphatic drainage on hemodynamic parameters in patients with heart failure and lower limb edema

Manual lymphatic drainage (MLD), intermittent sequential pneumatic therapy (ISPT), multilayered bandages (MLB), and compression garments are main techniques in conservative treatment of peripheral lymphedema. Since 1990, it has been thought that ISPT applied to both lower limbs simultaneously should not be used for patients with heart failure because right atrial, pulmonary arterial, and pulmonary wedge pressures may increase to a critical point. In 2005, these same results were observed in patients with heart failure wearing MLB. For these reasons, MLB and ISPT have been contraindicated during lymphedema treatment in cardiac patients. The aim of this study was to determine if we may continue the treatment of lower limb lymphedema using MLD in patients with heart failure. We evaluated hemodynamic parameters using echography during MLD in patients with cardiac disease and obtained circumferential measurements of the edematous limb before and after treatment. MLD treatment significantly decreased the limbs as expected. The heart rate also decreased following MLD in contrast with all other hemodynamic parameters which were not affected by MLD. The findings suggest that there is no contraindication to use MLD in patients with heart failure and lower limb edema.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Radiation-resistant erbium-doped-nanoparticles optical fiber for space applications

International audienceIn the last decade, there has been increased interest in photonic technology for new satellite applications. One critical issue is the high sensitivity to radiative environments of the Erbium Doped Fiber (EDF). It leads to a radiation-induced absorption (RIA) that is not due to erbium content but mainly to the aluminium that ensures the erbium inclusion in glass. As the radiation induced losses grow as an exponential function of fiber length, the principal way so far to reduce EDFA degradation has consisted in increasing erbium concentration using conventional doping techniques. However, this is limited by the quenching effect, which impacts the fiber length needed to reach high gain, but also by the Aluminium-induced RIA. It has been recently proposed an original nanoparticle (NP) doping approach, which allows codopant content decrease with reduced quenching impact, while keeping EDF amplifying performances. A radiation-resistant amplifier can thus be designed as a "quenching-free", heavily-erbium-doped amplifier with low RIA. We demonstrate for the first time an aluminium-free EDF, exhibiting low quenching and low RIA. Despite the lack of aluminium, using silica NPs allows an erbium concentration close to the one of standard EDFs (200 ppm). This fiber is compared to a 1400 ppm Erbium-doped optical fiber with a strong aluminium concentration. Whereas the two fibers exhibit similar initial optical gain (15 dB under saturation conditions), the NP doped Al-free EDF shows only 2 dB gain reduction after a 600 Gy gamma deposit, while the Al/Er EDF incurs more than 10 dB gain degradation

Recent developments in optical fibers and how defense, security and sensing can benefit

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Study of radiation effects on Er3+^{3+}-doped nanoparticles germano-silica fibers

International audienceThe main goal of the present work is to study the impact of Er–SiO$_2$ and Er–Al$_2$O$_3$ nanoparticles on the radiation induced defects in germano-silica optical fibers with Al/Ge ranges over 0.1–150. These fibers are prepared by a modified chemical vapor deposition technique and are characterized by optical absorption and electron paramagnetic resonance spectroscopy. High amount of Ge, Er–SiO$_2$ nanoparticles-derived optical fibers exhibit lower radiation induced attenuation than those with a low Ge content undoped or doped with Al$_2$O$_3$ nanoparticles. Furthermore, the behavior of point defects namely GeE’, Ge(1), SiE’, nonbridging oxygen hole centers, and H(1) is reported according to the Al/Ge ratio. In contrast to the optical fiber preforms, no Al-related defects are found in the optical fibers. Therefore, the results evidence the strong radiation tolerance by the virtue of the nanoparticle doping, which is enabling technology for the development of the photonic and space applications in the radiation fields